A new apparatus to conduct impregnation of granular materials has been developed to facilitate specimen preparation for microstructure observations. New experimental and analytical procedures have been presented to quantify the nonuniformity and anisotropy of granular materials. The nonuniformity of porosity distribution within a specimen was evaluated using imaging techniques. The anisotropy analysis consisted of the directional distribution of local porosity and orientation of solids and voids.

The procedures have been used to study the fabric of granular specimens prepared from Ottawa sand, silica sand, and spherical glass beads. The relation between directional porosity and the preferred orientation of granular particles and voids was found to be highly dependent on their angularity and elongation.